Here's an older thread that has some good info. I just got my hardtop at the end of October.
http://www.986forum.com/forums/showthread.php?t=1607&highlight=spinlock
According to everyone on the web, they are called spinlocks. According to the dealer, they are not. They knew what I was asking for though. About $100 +/- depending on where you get them. Mine were a little more since I went to a high priced dealer and I needed them that day.
-David